A rotatable connector device such as a steering roll connector or the like which is mountable on a vehicle such as an automobile or the like includes a cable housing having a stator (fixed case) and a rotator (rotatable case) which are coaxially attached to each other so as to be rotatable with respect to each other.
In the cable housing of such a rotatable connector device, the stator is fixed to a vehicle body and the rotator is attached to the steering wheel. In addition, the rotatable connector device electrically connects the vehicle body side and elements on the side of the steering wheel, for example, a horn module, an airbag module and the like via flat cables accommodated in an accommodation space in the cable housing.
Patent Document 1 describes an example of such a rotatable connector device. A retainer (guide member) for guiding flat cables (band-like transmission lines) accommodated in an accommodation space (ring-shaped space) formed in a cable housing is located on a bottom surface of the accommodation space.
The retainer includes a plate-like guide ring which is C-shaped when seen in a plan view and is located on the bottom surface of the accommodation space so as to be rotatable around a rotation axis of a rotator, and a plurality of rollers axially supported so as to be rotatable around a rotation axis parallel to the rotation axis of the rotator. The guide ring is equally divided into a plurality of areas in a circumferential direction thereof, and the plurality of rollers are respectively provided in the plurality of areas.
The flat cables are accommodated in the accommodation space in a wound state. Inner ends of the flat cables in a radial direction are wound around an inner cylindrical section (inner cylindrical axial section) of the rotator, and outer ends of the flat cables in the radial direction are wound around an outer circumferential cylindrical section (outer cylindrical section) of a stator. An intermediate portion of the flat cables is turned around in a U shape.
As shown in FIG. 7, a steering column cover includes a steering lower cover K and a column cover L, and an opening M is formed to communicate between the steering lower cover K and the column cover L. The rotatable connector is accommodated in the opening M on the side of the column cover L.
However, the rotatable connector has the following problem. A clearance N is formed between the steering lower cover K and the column cover L. A gap P is formed between a circumferential edge of a stator 12 and a circumferential edge of a rotator 13 facing the circumferential edge of the stator 12, and the gap P is located so as to face an intermediate position of the clearance N. Therefore, a foreign object Z such as, for example, sand, trash, dust or the like is likely to enter an accommodation space S in a cable housing 11 through the gap P between the stator 12 and the rotator 13.
When the foreign object Z enters the accommodation space S in the cable housing 11 through the gap P between the stator 12 and the rotator 13 in this manner, flat cables C which are wound or unwound by relative pivoting of the stator 12 and the rotator 13 are rubbed with each other. As a result, there occur problems that the flat cables C are broken, lamination covers of the flat cables C are delaminated to cause shortcircuiting, or an unusual sound is generated when the flat cables C are rubbed with each other. There is another problem that the resistance against pivoting of the stator 12 and the rotator 13 is increased to deteriorate the operability of the rotatable connector.